Clarification on Rules for Designs and Such

All right, so Imperium Divinium noted that one design I was offering to someone else was an absolute monster in the context of what was actually happening in the Late Nineteenth and Early Twentieth Century, and would have made most historical battleships of that time period obsolete due to its design being for extreme speeds and only big guns, stripping away armour and survivability to accomplish this. 

I can see where he is coming from with regards to it, as it would pretty much make 'battleships' obsolete and make torpedo boats the kings of the sea. So, how does everyone feel about this issue? Should we allow people to use ship designs that are not historical and depart vastly from the conventions and wisdom of the day but keep to the technology, or should we ban it?

Oh, and we might as well discuss. How does everyone here feel about us limiting fleet sizes to around 250.000 tons? Also, who is the blue chain of islands? - It was Neo-Valencia!